Liquid detergent concentrates for use in the vehicle washing industry are conventionally shipped in large containers. Typically, a line is attached to the container containing the large amount of liquid detergent concentrate, and a portion of the liquid detergent concentrate is drawn off for each vehicle washing cycle. Shipping large concentrates of liquid detergent can be expensive. In addition, disposal of the container that holds the liquid detergent concentrate can be problematic.
As an alternative to shipping large volumes of liquid concentrate, large volumes of liquid concentrate can be generated on site by mixing a detergent powder with water. Once the liquid concentrate is used up, a new batch of liquid concentrate can be prepared. One technique for preparing a liquid concentrate from detergent powder is by submerging the detergent powder in a tank filled with an aqueous solution. This technique requires an operator to place detergent directly into standing water. Splashing caused by adding the detergent directly into the concentrated solution and/or mechanical mixing using a mixing blade can pose a safety hazard.
Much attention has been directed by Ecolab Inc., the assignee of this patent application, in preparing liquid detergents from solid detergent concentrates. This focus of attention has been directed mostly at warewashing and clothes washing. See, for example, U.S. Pat. No. 4,687,121 issued to Copeland et al; and U.S. Pat. Nos. 4,569,781 and 4,569,780 issued to Fernholz et al.